1. Field of the Invention
The present invention relates to an apparatus for winding a tape spirally on a core for insulation or other purposes in the manufacture of an electric wire or cable.
2. Description of the Prior Art
A conventional apparatus for winding two tapes on a core is shown in FIGS. 1 and 2. The apparatus includes a spindle 1 having an axial bore defining a core passage, and supported rotatably on a stand 3 by bearings 2, 2'. A pulley 12 is attached to the spindle, while another pulley 14 is connected to the output shaft of a motor 13. A belt 15 extends between the pulleys to transmit the rotation of the motor to the spindle. A pair of holding shafts 5, 5' are provided symmetrically on the opposite sides of the spindle. A pair of tape reels 4, 4' are rotatably supported on the holding shafts, respectively, by a pair of springs 6, 6' which apply a braking force to the reels, and a pair of nuts 7, 7' holding the springs. The spindle is provided with guide rollers 9, 10 for a tape 8. A core 11 is passed through the axial bore of the spindle. The tape reel 4 carrying a supply of tape 16 is mounted on the holding shaft 5, and the tape is passed around the guide rollers and fastened to the core. If the spindle is rotated and the core is advanced in the direction of an arrow in FIG. 1, the tape is unwound from the supply of tape and wound on the core. The winding mechanism on the opposite side of the spindle is used in the same way.
In the apparatus hereinabove described, the tape reel is rotated about the core to wind the tape spirally on the core. If its rotating speed is increased, a centrifugal force and a wind pressure cause the failure of the tape to be fed smoothly and wound properly on the core. The wind pressure creates a particularly great amount of trouble. As the tape reel is relatively large and constitutes a large resistance to the air, it agitates the ambient air and creates a strong wind if it is rotated at a high speed. This wind renders the movement of the tape unstable, and even causes it to come off the guide rollers if the tape tension is insufficient.